Rubber mixer



RUBBER MIXER 3 Sheets-Sheet 1 Filed Dec. 18. 1958 IN VEN TOR HARRY D. WALTHER M g M ATTORNEY- O t 24, 1 61 H. D. WALTHER 3,005,229

RUBBER MIXER Filed Dec. 18, 1958 3 Sheets-Sheet 2 FIG. 4

(n 2 LL VENTOR. HARE WALTHER M azfl w x ATTORNEY Oct. 24, 1961 H. D. WALTHER 3,005,229

RUBBER MIXER Filed Dec. 18. 1958 3 Sheets-Sheet 3 IN V EN T HARRY D. WALT ATTORNEY United States Patent 3,005,229 RUBBER MIXER Harry D. Walther, Waterford Township, Erie County, Pa., assignor to Skinner Engine Company, Erie, Pa., a corporation of Pennsylvania Filed Dec. 18, 1958, Ser. No. 781,329 1 Claim. (Cl. 18-2) This invention relates to rubber mixers and, more particularly, to a rubber mixer of the Banbury type, and is particularly concerned with the provision of a novel form of discharge door carrying means for the discharge opening at the bottom of the chamber of the mixer.

Mixers of this type comprise what is usually referred to as a double cylindrical chamber, the chamber consisting of two cylinders placed side by side with their axes in parallel horizontal relation and the cylinders communieating with each other at their adjacent portions or at the portions lying between their axes. A rotor is provided in each of the cylinders, each of the rotors being provided with blades, the tips of which approach closely the walls of the respective cylinders. The chamber formed by the two communicating cylinders is provided with a bottom discharge opening at the center of the chamber and extending lengthwise across the center. To close this opening, a sliding door is provided so that after a batch of rubber or other plastic material has been treated in the machine, the door may be moved outwardly to open position and allow the batch to drop by gravity from the chamber.

The door has a groove formed at its lower portion to fit over a key on top of the sliding door cylinder and the door is fixed thereon. In the past, the sliding door cylinder had wings or lugs integrally cast on the cylinder. These integral wings extended out beyond the gear end of the cylinder and the cylinder ways were bolted there on. These ways sliding on the machine frame carried the cylinder. These integral wings extending beyond the end of the cylinder have proved unsatisfactory since the cylinder is made of cast iron which is ordinarily brittle and, due to the extreme presure brought to bear on the cylinder and its integrally supporting wings, the extending portion of the wings received uneven pressure, causing the ends of the wings to snap oh. This failure can be caused by a number of different reasons, ranging from the necessary clearance that is maintained between the door and the mixer, the material from which the cylinder is cast, the contamination of the Ways by the ingredients being mixed, and, of course, the extreme pressure brought forth in loading and adding ingredients.

It has been discovered that with the wing portions cast integral with the cylinder cover rather than as a continuation of the ways on the cylinder, even though the cylinder cover is doweled and bolted to the cylinder, there is some give between it and the cylinder cover and, therefore, the wing portions do not break 0E.

The invention disclosed herein and illustrated as a preferred embodiment of the invention relates to an improvement of the sliding door cylinder and its integral wings. The integral wings are now east to the cylinder and terminate at the ends of the cylinder. The cylinder cover was formerly made of three separate parts welded together. The improved cylinder cover is made of a casting of steel with integral wings cast thereto so that the wings cast on the cylinder cover form continuations of the wings cast integrally with the cylinder. This is an improvement over the structure of the sliding door cylinders now employed and shown in the prior art.

It is, accordingly, an object of this invention to overcome the dis-advantages in prior machines of the type described and, more specifically, it is an object to provide 3,005,229 Patented Oct. 24, 1961 i 2 a machine which is simple in construction, economical to manufacture, and simple and efficient inoperation.

Another object of the invention is to provide an improved mixer for plastic materials.

A further object of the invention is to provide a mixer for plastic materials of the Banbury type having improved support wings and cylinder covers torsupport on corresponding ways.

With the above. and other objects in view, the present invention consists of the combination and arrangement ofparts hereinafter more fully described, illustrated in the accompanying drawings and more particularly pointed out in the appended claim, it being understood that changes may be-made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings: v

FIG. 1 is a side view of a sliding door cylinder;

FIG. 21 is a cross sectional view taken online 2-2 of j FIG.

FIG. 3 is an end view of the inner side of the gear cylinder cover according to the invention;

FIG. 4 is a cross sectional view taken on line 4-4 of FIG. 3;

FIG. 5 is a side view of the mixer; and

FIG. 6 is a cross sectional view taken on line 6-6 of FIG. 5.

Now with more specific reference to the drawings, a mixer is shown comprising a chamber 10 having a charging stack 11 at the upper portion thereof. The charging stack 11 is provided with end walls 12 which are continued downwardly to form the end walls or plates for the chamber 10.

As shown, the chamber 10 is of the double cylinder type consisting of two cylinders 13 and. 14, in each of which is mounted a bladed rotor 15. As will be seen from FIG. 6 of the drawings, the two cylinders 13 and 14 communicate with each other at their adjacent portions so as to form a chamber of substantially double cylindrical shape.

At the lower portion of the chamber and at the central portion thereof is provided a discharge opening 16, the opening 16 being closed by a door 17 which in this instance is slidably mounted to be moved to an open and closed position. The door or closure member 17 is keyed or otherwise secured to a cylinder 18 which is provided with wings 19. The wings 19 are adapted to extend laterally over ways 20 disposed on the lower base portions 21 of the chamber 10. The door 17 is adapted to be moved to open and closed positions by means of fluid pressure introduced into opposite ends of the cylinder 18. The fluid pressure works against a piston 23 mounted on a piston rod 24, the outer end of which is rigidly held at 25 in a base portion 26 of the mixer. As the piston 23 is thus fixed against longitudinal movement, it will be understood that introduction of fluid pressure upon one side or the other of the piston 23 will affect movement of the cylinder 18 and the door 17 in opposite directions to open and closed positions.

Heretofore, in mixing machines of this characer, the wings 19 were cast integral with the cylinder 18 and extended axially beyond the end of the cylinder 18 and the cylinder cover. The wings were bolted to ways separately from an end shield 22. The end shield was bolted to the end of the cylinder between the ways. The end shield was made by welding three separate parts together.

In the present disclosure, the wings 19 terminate at the end shield or cylinder cover 22. Extending wing portions 27 are separate from the integral wings 19 of the sliding door cylinder 18. The cylinder cover 22 has the extending wing portions 27 cast integrally. The wing portions'27 form a continuation of the wings 19.

Bolts 28 are disposed in-holes 32 and fasten the cylinder cover 22 to the end of the sliding door cylinder 18. The Wings 19 and the extending wingportions 27 have drilled countersunk holes 29 to receive studs to hold a cylinder way 30 in position with the base side way 20. The cylinder cover 22 has drilled pipe threaded holes 31 adjacent a periphery 33 to receive the fluid which will activate the cylinder 18.

The foregoing specificationisets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claim. v

- The embodiments of the invention in which an exclusive property or privilege is claimed are definedvas follows:

A mixer for heavy plastic materials comprising a double cylindrical chamber having a bladed rotor in each of the cylinders thereof, said chamber being provided with a bottom discharge'opening, a slidably mounted closure member for said opening, the upper side of said closure member comprising two plane surfaces meeting at a line substantially centrally of said chamber and the surfaces sloping inwardly from the side edges, said slid ably mounted closure member comprising a cylinder,

said closure member mounted on said cylinder, the axis of said cylinder being parallel to a ridge, a piston in said cylinder, said piston having a rod attached thereto and connected to said mixer and extending from sadi cylinder, fluid means on each side of said piston in said cylinder forcing said cyilnder to a closed and to an open position, a cylinder cover bolted to the end of said cylinder remote from said rod, ways on said mixer, a first wing References Cited in the file of this patent UNITED STATES PATENTS 2,299,502 Schnuck et a1. Oct. 20, 1942 2,432,088 Caldwell Dec. 9, 1947 2,478,832 McManis Aug. 9, 1949 2,725,220 Hale et al Nov. 29, 1955 

